With nothing but stars to guide them, the ancient Polynesians
navigated one-quarter of the Earth and discovered heaven in the
form of the Hawaiian Islands. When they wanted to return to that
paradise, they navigated the open ocean by a single star that hangs
reliably over the big island in spring. We know it as Arcturis;
they called it Hokule'a, or "the guide star."

Solar physicist Arthur Bertram Cuthbert Walker II has spent a
lifetime bridging the space that separates humans from the Sun and
from each other. On Sept. 15, Walker got his own day in the sun at
a celebration of his achievements sponsored by the departments of
Physics and Applied Physics and the African and Afro-American
Studies Program.

Professor
Calvin Quate (right) and Emeritus Professor Sylvia Wynter (center)
were among those who celebrated the achievements of Art Walker
(left).photo: L.A.
Cicero

"By
your example, you've been the guide star, the Hokule'a, for those
of us on the faculty, and for the many students that you've
educated here in physics at Stanford," Applied Physics Chair Bob
Byer told Walker.

Master of ceremonies Ewart Thomas, professor of psychology,
said: "We celebrate Art's innovative research and inspiring
teaching in physics, particularly in solar physics, his exemplary
contributions to the black community at Stanford, and the abundant
love and support Art has given as son, father, husband, cousin and
friend to many."

Students, colleagues, friends and family came from near and
far to share tales of Walker, who has been a professor of physics
and applied physics at Stanford since 1974. Cousins flew in from
New Jersey, Georgia and Texas. Members of the Sigma Pi Phi
fraternity for black professionals, of which Walker is a member of
long standing, drove in from throughout the Bay Area. NASA
administrators made the trip from Washington, and the director of
the National Optical Astronomy Observatories came from Arizona.
Faculty whose research ranged from Ebonics to electronics gathered
at the Faculty Club for the reception and dinner along with
Walker's wife, Victoria, and two of his three children.

Walker is world renowned for his pioneering use of X-rays and
thin films to study the Sun's outermost atmosphere. The excitement
engendered by his stunning images of the Sun are a big reason solar
physics enjoys a high profile, said NASA program scientist William
Wagner: "It's the reason probably that there'll be a new initiative
by NASA in this coming year by the name of 'Living with a Star.'"
The initiative aims to study solar activity; six telescopes in
parallel, Walker-style, will take high-resolution pictures of the
Sun every 10 seconds.

For
more than a quarter-century, Walker has directed Stanford's student
observatory and taught astronomy courses including the popular
Applied Physics 15 ("The Nature of the Universe") and Physics 50
("Observational Astronomy"). He has guided the graduate careers of
13 past Ph.D.s and five current candidates. Among them, seven
belong to groups that are underrepresented in physics. His most
famous doctoral student is Sally Ride, America's first woman in
space.

He
has served as associate dean of graduate studies and as a member of
graduate student admissions committees for the departments of
Physics and Applied Physics. NASA's Phil Sakamoto calls Walker's
dedication to bringing underrepresented students into the space
sciences program "legendary." A constant stream of his students has
received NASA's highly competitive fellowships for graduate student
researchers.

"There are no words to express our gratitude to you for being
our teacher, mentor, friend and champion," said Dennis
Martinez-Galarce, one of nearly a dozen former students at the
tribute. "Your Harvard B School style of management gave us the
opportunity to think independently, to be creative and to challenge
ourselves to understand the research we were performing and the
amount of work that was required to accomplish it."

A
recent Ph.D. in electrical engineering, Martinez-Galarce now works
at Stanford's Hansen Experimental Physics Lab with Walker and
physics Professor Blas Cabrera on a project to image energy flows
between layers of the Sun's atmosphere.

"Because of Art's efforts, Stanford led the nation among our
peer institutions in educating to advanced degrees underrepresented
minority students in the physics degree," said Byer.

Walker's recommendations to Congress were instrumental in
creating a national solar observatory. And in 1986, President
Reagan appointed Walker to serve on the commission that
investigated the space shuttle Challenger explosion -- the
"JFK event" of a generation -- and concluded that the disaster was
preventable.

Alive with
activity, the surface of the Sun is characterized by coronal coils,
gaseous geysers and other violent visuals revealed by NASA's
Multi-Spectral Solar Telescope Array (MSSTA).Courtesy:
NASA/Art Walker

Midway through the September celebration, NASA officials
surprised Walker with a Distinguished Public Service Medal in
recognition of "four decades of distinguished scholarship,
achievements in experimental space sciences and extensive service
to NASA and the nation on innumerable advisory and review
boards."

The Sun you never knew

Don't stare at the Sun -- you'll go blind, mothers warn
their children. But technology that Walker developed with materials
scientist Troy Barbee of Lawrence Livermore National Laboratory
lets us take a closer look at the Sun than ever before.

While a senior research associate at Stanford's Center for
Materials Research in the 1980s, Barbee created multilayered thin
films so perfect that they could be considered crystals. This
property enabled them to capture images produced by hot solar gas
so energetic that it spewed radiation in the extreme ultraviolet
end of the spectrum.

"One of the things I have learned over the years as a
materials scientist is that materials don't do anything;
people do things with materials," Barbee said. "Art has taken those
things which I was able to put on the table and use them to
demonstrate new science and develop new technologies."

In
1987, Walker developed telescopes and complex instrumentation,
mounted them on satellites and launched them into space to escape
the interference of the Earth's atmosphere. There they captured the
first detailed pictures of the Sun's outermost atmosphere, or
corona, the halo of light seen by the unaided eye during a total
solar eclipse. Images from the first flight of Walker's solar
telescope appeared on the cover of Science magazine on Sept.
30, 1988.

"It
was a spectacular achievement," Byer recalled.

"Right away people saw that this technique worked," said Phil
Scherrer, a research professor of physics. NASA and European Space
Agency scientists designing the Solar and Heliospheric Observatory
(SOHO) rushed to put Walker's instrument onboard.

Walker launched 14 telescopes in NASA's first Multi-Spectral
Solar Telescope Array (MSSTA) flight in 1991. The second flight, in
1994, had 19 telescopes.

Why
so many? A telescope's flight filter only lets in one wavelength of
light at a time. "One wavelength is going to look at one
temperature in the Sun," explained Scherrer, displaying Walker
photos of solar activity at two temperatures -- 25,000 degrees and
1.5 million degrees Kelvin. "To look at different temperatures at
different heights in the Sun, you need a whole collection of them.
Things happen at all different temperatures at the same
time."

Images that show how the Sun's temperature changes in
different regions will give scientists a greater understanding of
solar activity.

For
reasons that still puzzle scientists, the corona is 1,000 times
hotter than the Sun's visible surface. A close look reveals that
this seemingly benign, fuzzy ball is downright violent.

Hot, electrified gas in the corona produces high-energy
particles and solar wind that disrupt the Earth's magnetic field to
produce colorful auroras and wreak havoc with telecommunications,
electric power, radar and weather.

"The solar wind -- the impingement of charged particles on the
Earth -- greatly enhances that amount of lightning we see, and in
fact all the great fires in the forests this summer are really tied
to [peak solar activity]," Barbee said. "We should understand that,
and we should understand how that affects us. What Art has done is
going to give us that opportunity."

Walker's technique also has been used in NASA's Chandra X-ray
observatory, to study the nighttime sky, and in a worldwide chain
of ground stations called the Global Oscillation Network Group
(GONG), to study solar activity.

A star is born

Walker's paternal grandfather, James Henry Walker, was a
schoolmaster who emigrated from Barbados to St. Vincent with his
wife, Millicent, around the turn of the century and placed great
expectations of scholastic excellence on his four daughters and
four sons. His second son, known as Cuthbert, was Walker's father.
Cuthbert came to New York to study at City College and work for the
Erie Railroad. When the Depression struck and the railroad's
headquarters relocated to Cleveland, Cuthbert moved with his job.
In Cleveland, he attended John Marshall Law School and met his
future wife.

Local star
makes good. Walker's techniques produced this image of the Sun,
which lit up the Sept. 30, 1988, cover of Science
magazine.Reprinted with permission from Science magazine, copyright
1988 American Association for the Advancement of Science.*

Walker's maternal grandfather, Ormand Forte, emigrated from
Barbados to the United States with his wife, Ida. He attended
Macalester College in St. Paul and worked for Hanna Steel in
Cleveland, where he attracted the interest of steel magnate Mark
Hanna, who supported his aspiration to set up an African American
newspaper in Cleveland. Walker's mother, Hilda, was born in 1911,
four years before her father launched his first newspaper, The
Advocate, which grew in influence and spawned three other
papers.

Arthur Walker was born in Cleveland on Aug. 24, 1936. He was
an only child but was close to his many cousins. In 1941 the family
moved to New York, where Walker's father set up his own law
practice.

From an early age, Arthur loved science. Hilda and Cuthbert
both sought to provide the best for their son, but it was Hilda who
played a pivotal role in making sure young Art had the
opportunities to pursue the kind of career that he
wanted.

When his elementary school in New York's Sugar Hill area had
an absentee problem -- with its teachers -- Hilda Walker
organized the other parents to stand at various locations of the
school and record the comings and goings of teachers ditching class
to run errands. When the parents presented these data to the
authorities, the officials solved their problem by transferring
young Arthur -- and therefore Hilda -- to a school outside their
district.

In
his new school, Walker discovered the library and the world of
science. To study the universe like Albert Einstein became his goal
-- so much so that his mother encouraged him to take the test for
the Bronx High School of Science.

"He
developed a keen interest in chemistry there," said Stanford's
Thomas. "But his chemistry teacher was worried about the job
prospects in the U.S.A. for a black chemist, suggesting that maybe
he would have better luck in Cuba." When that teacher tried to
steer Walker away from physics as well, Hilda paid a visit to the
school and told him "in no uncertain terms" that her son would
study whatever he wished, said Walker's cousin Asquith Phills, an
Exxon executive.

Walker decided to pursue physics, and his mother encouraged
him to apply to the Case Institute of Technology in Cleveland. He
received his baccalaureate in physics with honors in 1957. At the
University of Illinois, he earned his master's degree in 1958 and
doctorate in 1962 with a dissertation on the use of radiation to
produce the particles that bind protons and neutrons together in
the atomic nucleus.

Walker joined the U.S. Air Force in 1962 as a first lieutenant
and was assigned to the Air Force Weapons Laboratory, where he
developed instrumentation for an experiment that involved rocket
launch of a satellite to measure Van Allen belt radiation in the
Earth's magnetic field. This radiation affects satellite operation.
Walker said this work ignited his interest in research carried out
with space techniques.

Upon completing his military duty in 1965, he joined the Space
Physics Laboratory of The Aerospace Corporation, where for nine
years he conducted pioneering physics experiments to study the Sun
and upper atmosphere of the Earth.

Helping black faculty and students shine

In
1973, the year before he joined Stanford, Walker was offered a
professorship at another top research university. "I decided not to
accept that one," he recalled. "I remember when I went to visit
that institution, the president said, 'We have one Chicano faculty
member here on our campus, and if you come and join us, you'll be
the first African American faculty member on our campus.' I said,
'That's kind of interesting, but I'm not sure that's exactly what I
want.'"

Peter Sturrock, now a Stanford professor emeritus of applied
physics, and Arthur Bienenstock, now associate director of the
Stanford Linear Accelerator Center, asked Walker to visit Stanford,
where he met with Halsey Royden, dean of the School of Humanities
and Sciences, and Jim Gibbs, dean of undergraduate
studies.

"They said to me, 'We think we have here at Stanford the most
distinguished African American faculty of any major research
university, and we hope you'll come and join us.' And I said, 'Now
that's the kind of attitude I want to see at the university
I join.'"

Underrepresented academics have long been placed in the
difficult position of splitting their time between activities
necessary to achieve tenure and serving as committee members or
mentors to boost the number of underrepresented
students.

Somehow Walker survived this Catch-22. "Art Walker has been an
inspiration to so many faculty here at Stanford, particularly young
black faculty," political science Professor Condoleezza Rice said
in an interview. "I count myself among the many former assistant
professors who looked up to him as someone who was proof positive
that promotion and advancement were possible at Stanford if you
successfully combined research and teaching."

Walker has served on the African and Afro-American Studies
program advisory committee longer than any other member, said
program director John Rickford, who holds the Martin Luther King
Jr. Centennial Professorship.

"Not as well known is the fact that he's very active on behalf
of the African American faculty," Rickford said. "There's no formal
black faculty association, but for many years Art served as its
informal president."

Walker called this informal association "The Banneker Group"
after the first African American man of science, Benjamin Banneker
(1731-1806). A free man, Banneker was largely self-educated and
owned a farm near Baltimore. In 1761, he built a wooden clock that
kept precise time; he accurately predicted a solar eclipse in 1789
and published almanacs from 1791 to 1802. He sent a copy of his
first almanac to Thomas Jefferson, then secretary of state, with a
letter asking Jefferson's aid in bringing about better conditions
for American blacks. Jefferson shared the almanac with European
scientists, who praised its accuracy.

Banneker also wrote poetically about stars and other celestial
bodies, and Walker would share this poetry with faculty who
gathered at a telescope on a hill to view a heavenly event.
Rickford said the poetry gave him "a sense of the joy that Art
feels when he looks at the stars."

The
Banneker Group pushed for more black faculty, for the African and
Afro-American Studies program to have its own billets and for a
research institute to study race and ethnicity.

"All of us benefited from Art's activities on our behalf and
were in turn grateful for them," Rickford said. "His involvement
was all the more remarkable because he didn't come from African
American literature or African American history or sociology or
anthropology, or any of the many fields that normally intersect in
a very natural way with African and Afro-American Studies. Here was
a person who was doing this with no political or professional
advantage of his own to be gained. It was purely his concern for
the larger issues that were involved."

Superstars under pressure

"Stanford's physics community is the most exciting place in
the world to do physics," said Walker, who has students and
colleagues in the departments of Physics, Applied Physics,
Electrical Engineering, Materials Science and Mechanical
Engineering, as well as at the Stanford Linear Accelerator Center.
"It's wonderful to walk down the hall in the physics building. If
you're not careful, you'll stumble across a Nobel Prize winner
who's doing something extremely exciting, inventing something that
you may yourself be able to use in your own research."

But
being part of Stanford's star-studded physics community is not just
about research. It's about people. And people, with their egos and
agendas and opinions, are not as easy as protons.

Nobel Prize-winner Professor Steve Chu said he appreciates
going into the astronomer's office to "chit-chat about everything,"
including waxing and waning stresses in the department: "He'd just
say, 'Well, let's figure this out,' and tell me what he thought. He
was in fact the Physics Department ombudsman. . . . Art saw right
through all the clutter of what was going on and had very wise and
soothing things to say."

Clutter is something Walker is used to, colleagues teased.
Every horizontal surface in the astronomer's office is piled high
with reprints and manuscripts. Chu presented Walker with a book
about Superman at the tribute. Its inscription read: "To Art, for
your X-ray-like ability to see through all the clutter and arrive
at the core of a difficult problem; for your soothing counsel to
students and faculty and in championing truth and justice, which is
not exclusive to the American way; for your rocket-borne
experiments that have leapt over tall buildings in a single bound,
I give you this book of one of my childhood heroes, of which there
is a bit in common."

Called to serve

Public service on the part of scientists is crucial to the
federal government, as Congress uses committee advice almost like a
blueprint to see that federal agencies are following the
recommendations of the scientific community. Throughout his career,
Walker has led or served on innumerable NASA, National Science
Foundation and National Academy of Sciences committees.

Walker's committee service helped build America's network of
astronomical observatories. He played the title role in the Walker
Committee, which recommended that the national observatories take
over the Sacramento Peak Solar Observatory when its Air Force
funding was cut. "[That change] gave us the critical mass so that
we can truly say that we have a national solar observatory," said
Sydney Wolff, director of the National Optical Astronomy
Observatories.

In
1986, President Ronald Reagan called Walker to serve on one of the
most important committees in U.S. history -- the commission
investigating the space shuttle Challenger explosion. The 13
commission members, chosen for their professional expertise in
engineering, industry, law, science and flying, included Apollo 11
commander Neil Armstrong, former Secretary of State William Rogers,
Nobel Prize-winning physicist Richard Feynman and Walker's former
student, astronaut Sally Ride.

"The Challenger accident occurred something like the
25th space shuttle mission in," said NASA's Wagner. "We're now, as
a result of the Challenger Commission and Art's work,
getting NASA back into space with the shuttle. We're now about to
launch the 100th space shuttle, so there were definitely things
done right."

Never the same space twice

As
the human race pushes the envelope of the known universe,
technology developed by Walker and others will continue to be its
collective eyes. Walker's X-ray images revealed a new face of the
Sun.

And
as technology evolves, the next generation will see something new,
too. Walker and Cabrera have just begun a collaboration to use
X-ray spectroscopy to create colorful 3-D images that reveal the
compositions of celestial bodies.

Said Walker: "I truly believe that if we are successful, this
will revolutionize X-ray spectroscopy, bring X-ray spectroscopy and
X-ray observations to the same level as optical observations in
astronomy and really revolutionize our understanding of the
universe."

*** The image
of the Science magazine cover is reprinted with permission from
Science magazine,
copyright 1988 American Association for the Advancement of Science.
Readers may view, browse and/or download material for temporary
copying purposes only provided these uses are for non-commercial
personal purposes. Except as provided by law, material may not be
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performed, displayed, published, or sold in whole or in part,
without prior written permission from the publisher.

The Transition Region and Coronal Explorer (TRACE) satellite,
developed by the Stanford-Lockheed Institute for Space Research,
shows convection and other activity in the corona. Such images may
help scientists solve a solar mystery: Why is the Sun's upper
atmosphere hotter than its surface?Film courtesy TRACE